A world without chocolate. Say it ain’t so! Few cacao varieties are widely cultivated, and that’s a problem. Like many other crops, cacao is under constant threat from diseases and environmental challenges exacerbated by our tendency to grow only a few varieties with similar or identical genetic traits and defects. A narrow gene pool means that most commonly cultivated varieties of cacao are susceptible to the same diseases, and these blights can spread quickly. Whatever fungal mutation may arise, wherever drought may strike, however chocolate tastes may change — there will likely be cacao genes somewhere in the collection that can form the basis of new hybrids to meet future challenges.

Scientists have precisely targeted a single error on a human genome to partly remove an inherited disease from embryos. The study involved changing the mutation responsible for a blood disorder called beta thalassemia, which can lead to anemia and severe illness. To show that the method worked, the team from Sun Yat-sen University in Guangdong made embryos using cells taken from humans with the condition, then used molecular techniques to seek out the “point mutation” that caused it. In the past decade there has been a revolution in gene editing, largely thanks to a biological tool known as CRISPR/Cas9, which can seek out sections of genetic code, snip them and replace them. This latest technique, called base editing, is a more advanced version that can act on a single “letter” of the genetic code without breaking the DNA string.

Mosquitos harbor gut bacteria just like people do — and the bugs inside the bugs may hold a key to fighting malaria. Two research teams at Johns Hopkins University in Baltimore have found that tinkering with mosquitoes’ resident microbes can help them spread resistance to the malaria parasite. One used “weaponized” bacteria to deliver parasite-stopping proteins to mosquito guts. The other found that mosquitoes with a malaria-blocking gene have an unexpected mating advantage thanks to their microbes. What works in the lab doesn’t always work in the wild. Next year, the Hopkins researchers hope to try hatching malaria-resistant mosquitoes in a somewhat more realistic setting, a net-covered greenhouse-like field station in Zambia.

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December 27, 2018Let’s End the Year With Great ChocolateWe're winding down to the finish. As you look ahead to 2019, enjoy this hot cup of science and ponder your resolutions for the year. We hope they include Eureka.